isl_map_subtract.c: n_non_redundant: propage isl_ctx
isl_map_subtract.c: n_non_redundant: propage isl_ctx

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

UBERTC/isl,tobig/isl,Distrotech/isl,serge-sans-paille/isl,crossbuild/isl,serge-sans-paille/isl,crossbuild/isl,Distrotech/isl,KangDroidSMProject/ISL,BenzoSM/isl,KangDroidSMProject/ISL,abduld/isl,UBERTC/isl,epowers/isl,nicolasvasilache/isl,Distrotech/isl,nicolasvasilache/isl,SaberMod/isl-current,KangDroidSMProject/ISL,cfx-next/toolchain_isl-upstream,simbuerg/isl,nicolasvasilache/isl,evaautomation/isl,VanirLLVM/toolchain_isl,SaberMod/isl-current,Distrotech/isl,inducer/isl-mirror,VanirLLVM/toolchain_isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,inducer/isl-mirror,Distrotech/isl,BobSaget-Mod/libisl,epowers/isl,simbuerg/isl,pierrotdelalune/isl,SaberMod/isl-current,simbuerg/isl,nicolasvasilache/isl,PollyLabs/isl,evaautomation/isl,inducer/isl-mirror,pierrotdelalune/isl,KangDroidSMProject/ISL,PollyLabs/isl,jleben/isl,BenzoSM/isl,Meinersbur/isl,simbuerg/isl,Meinersbur/isl,epowers/isl,crossbuild/isl,UBERTC/isl,VanirLLVM/toolchain_isl,BobSaget-Mod/libisl,jleben/isl,KangDroidSMProject/ISL,tobig/isl,abduld/isl,pierrotdelalune/isl,BenzoSM/isl,BobSaget-Mod/libisl,nicolasvasilache/isl,pierrotdelalune/isl,SaberMod/isl-current,BenzoSM/isl,crossbuild/isl,pierrotdelalune/isl,inducer/isl-mirror,cfx-next/toolchain_isl-upstream,PollyLabs/isl,inducer/isl-mirror,cfx-next/toolchain_isl-upstream,jleben/isl,BobSaget-Mod/libisl,VanirLLVM/toolchain_isl,cfx-next/toolchain_isl-upstream,epowers/isl,PollyLabs/isl,VanirLLVM/toolchain_isl,serge-sans-paille/isl,jleben/isl,abduld/isl,epowers/isl,BobSaget-Mod/libisl,UBERTC/isl,abduld/isl,Meinersbur/isl,BenzoSM/isl,tobig/isl,Meinersbur/isl,PollyLabs/isl,serge-sans-paille/isl,jleben/isl,simbuerg/isl,tobig/isl,serge-sans-paille/isl,evaautomation/isl